Electron discharge tube



May 15, 1945.

C. H. SPHAR ELECTRON DISCHARGE TUBE Filed Jan. 27, 1942 INVENTORT CLARKH. SPF/AR.

ATTORNEYS.

-May15, 1945.Q C- H SPHAR 2,376,288

ELECTRON DISCHARGE TUBE Filed Jan. 27, 1942 2 Sheets-Sheet 2 36 r F ,20I I /7 I t I ,-/8 p30 2a {.3 I 4 3a 27 a IE: I f 41 26 r 1 4 *l I I I rIN V EN TOR CLARK H. SPHAR.

ATTORNEYS.

. Fig. 2.

Patented May 15, 1945 ELECTRON DISCHARGE TUBE Clark H. Sphar, SanFrancisco, Calif., assignor to Ltd., South San Francisco, of NevadaApplication January 27, 1942, Serial No. 428,373

Eilelntz & Kaufman, (Caiifi, a corporation 1 Claim.

My invention relates to electron discharge tubes, and more particularlyto a means for supporting electrodes within such tubes from the a manneras to minimize relative movements between electrodes; and to provide astrong sturdy and simple electrode support for elements to be positionedwithin an envelope.

Other objects of my invention will beapparcut or will be specificallypointed out in the description forming a part of this specification, but

I do not limit myself to the embodiment of .the

invention herein described, as various forms may be adopted within thescope of the claim.

My invention may be more fully understood by direct reference to thedrawings, wherein:

Fig. 1 is a view in side elevation of one preferred embodiment of myinvention as applied to a vacuum tube of the transmitting type.

Fig. 2 is a view partly in section and partly in elevation showing theelectrodes of the tube of Fig. 1 in detail.

Fig. 3 is a sectional view taken as indicated by the line 33 in Fig. 2.

Fi 4 is a view partly in section and partly in elevation taken asindicated by the line 4-4 in Referring to the figures for a detaileddescription of a preferred form of my invention, as 11- lustrated-anenvelope I, preferably of glass, such as heat resisting glass. isprovided at one end thereof with a reentrant stem 2 having an innerpress 3, through which pass a pair of filament supports 4. Filamentsupports 4 are provided out wardly with flexible conductors 5 which areconnected to contact pins 8 forming a part of a base 1 applied to thestem end of the envelope.

Immediately above the stem end of the envelope is positioned an enlargedportion of the envelope 9 terminating in an anode end In to which ananode cap II is sealed by a metal-toglass seal flange l2. The outer endof anode can II is provided with a large anode contact bin ll. The innerend of the cap is projected into the bulbous portion of the envelope asa tube i5. Tube II has attached thereto a plurality of radially anddownwardly extending anode support elements or g rders l6, these elemets preferably being of U-section, the lower ends be ng attached to finsl1 of a cylindrical anode I 3.

Anode I8 is provided at the top thereof and between support elements orgirders IS with a dome-top having a central aperture 2|. On one side ofthe tube, preferably adjacent the connection of the bulbous portion 9 tothe stem portion of the envelope, is a grid envelope arm 22 outwardlyterminated by a grid cap 23 sealed to the'arm 22 by a metal-to-glassseal flange 24. As with the anode seal, the outer end of the grid cap Iis terminated by a grid contact pin 25, the grid cap being projectedinwardly, concentric with arm 22 as a grid support tube 26.

Grid support tube 26 has welded thereto on opposite sides thereof,side-by-side girders 21 preferably of U-section, these girders divergingtoward the interior of the tube to terminate, as by welding, on a gridbase 28. Grid base 28, as will be seen in Fig. 2 supports a plurality ofgridwire hairpins 30 having parallel vertical runs, these hairpins beingjoined at the top to form a domed inner end 32 of the grid. Filamentsupports 4 extend upwardly inside grid base 28, and have semi-circularcathode connectors 33 and 34 welded to their respective upper ends.These connectors make conductive contacts, as by welding, with aplurality of upright filaments '35 welded to a disc 3-6 sliding on acentral filament support rod 31 embedded in-the stem press betweenfilament supports 4. Filament disc 38 is supported by a pair of discrods 38 extending upwardly inside the filament assembly, these disc rodsbeing attached together at their lower end and to a spring disc 39 alsosliding on rod 31. Spring disc 33 is forced upwardly, to keep thefilaments under tension by means of spring l0, bearing at its lower endagainst second spring disc 4| supported on a pair of spring positioningmembers l2 tied together by rivets or small screws 43, with insulatingmaterial such as mica between each half and each filament support I. Inthis manner the filament spring is kept well out of the heated portionof the tube. and therefore will maintain filament tension undercontinuous operation of the. tube. Tension on the spring may be adjustedby varying the position of clamp 42.

It will be noted that neither the anode nor the grid, which. are theelectrodes of greatest weight in the tube. are dependent upon wiresupports.

They are both supported from tubular elements. sealed to the tubeenvelope over a wide extent thereof, thusforming firm basis for thesupport of both anode and grid. Tubular supports of both anode and-gridare extended to support the anode and gr d bymeans of spaced girderbars. preferably of U-section. It is also to be noted that the grid issupported by the tube 28 and the girders 21 at an angle to both thevertical and horizontal, thus enabling the grid to more fully withstandshocks, than if the grid supports were extended only horizontally.Lateral and twisting movements of the grid is reduced by the boxarrangement of girders. Both grid and anode supports involve triangulararrangements of elements and are thus made exceptionally sturdy andresistant to displacement, the triangle being recognized as representingthe most rigid of the sirnple geometric figures. Small relativedisplacements of the elements are avoided, leading to efiicient andproper operation of the tube, particularly at high frequencies.

I claim: In an electrical discharge tube having a glass envelope andelectrodes therein to be supp rted by said envelope, an electrodesupport comprising a cylindrical conductive member projectinthrough'said envelope, a metal flange extending laterally around saidmember intermediate-the CLARK H. sPHAa. 1

